The present invention relates generally to novel devices for removing intravascular deposits, occlusions, and the like from a vascular system. More specifically, the invention relates to novel intravascular thrombectomy devices and methods of using the same.
Vascular diseases, such as arteriosclerosis and the like, inflict an ever increasing number of people in modern times. Some of these diseases are caused by deposits or growths formed within a vascular lumen, which may be located in the coronary, peripheral, or other vasculature. These deposits can be formed in a plurality of ways, may be formed from hard, calcified tissues or materials, thereby forming an atheroma, and the like, or may be formed from material free floating within the vascular system, like an embolus, which may become attached or lodged in a certain portion of the vasculature. Other deposits may be formed from soft tissues, such as a blood clot, growing in a relatively fixed place in the vasculature, such as a thrombus.
These various deposits or occlusions may only constrict a vascular lumen, thereby reducing blood flow through a particular portion of the vasculature, or may form a total occlusion of a particular lumen, thereby severely limiting or cutting off blood circulation to particular parts of a patient's body. Total occlusions can be of heightened concern if the occluded lumen supplies blood to a vital organ. In any case, such occlusions, whether partial or complete, can compromise a patient's health and well-being.
In an effort to alleviate some of the problems caused by the occlusions, many various methods of treatment have been developed in an effort to restore substantially normal circulation through the diseased portion of the vasculature. While invasive procedures, such as vascular bypasses, may be effective, it is desirable to use non-invasive, intravascular methods of treatment. By using these non-invasive procedures, the patient can experience less post-operative pain, necessary rehabilitation and a lower probability of infection.
One such non-invasive method is conventional balloon angioplasty wherein a balloon catheter is inserted intravascularly into a patient. The balloon catheter includes a dilating member which is placed adjacent the vascular occlusion and then is inflated. Intravascular inflation of the dilating member by sufficient pressures, on the order of 5 atmospheres, causes it to compress or mold the occluding matter to revascularize the occluded lumen thereby restoring substantially normal blood flow through the revascularized portion. It is to be noted, however, that this procedure only molds the occluding matter and does not remove that matter from the patient's vasculature.
While treatment by conventional balloon angioplasty can be quite successful in substantially removing some vascular occlusions, other occlusions may be difficult to remove by angioplasty, thereby making conventional angioplasty, by itself, an insufficient treatment method in some instances. Specifically, some intravascular occlusions may be composed of a particularly hard, rigid material which is not prone or susceptible to angioplastic molding. Such rigid occlusions may require pressures to mold the occlusion greater than those reasonably safe to introduce into a patient's vasculature. This consideration may take on added significance if the particular portion of the patient's vasculature to be treated is structurally weak.
Furthermore, if the occlusion is a blood clot or soft tissue thrombus, such as those that may occur in the peripheral vasculature, for instance, the soft tissues of the thrombus may sufficiently resist the molding action of the dilating member (i.e. may be too elastic) to prevent conventional angioplasty from permanently restoring vascular blood flow. In addition, even if the occlusion is successfully molded, thereby revascularizing the vessel and restoring blood flow therethrough, there is a chance that the occlusion may recur because the occluding material is not removed from the vascular lumen, thereby necessitating repeated or alternative treatments.
Given these considerations regarding conventional balloon angioplasty, other alternative methods of non-invasive, intravascular treatment have been developed in an effort to provide another way of revascularizing an occluded vessel and of restoring blood flow through the relevant vasculature. These adjunct treatments may offer a more effective alternative treatment to some patients than conventional balloon angioplasty, may have particular utility with a particular vascular occlusion., or may provide added benefits to a patient when combined with traditional balloon angioplasty.
Accordingly, the present invention is intended to provide novel treatment means or methods for .removing such a soft tissue vascular occlusion material, such as a thrombus and the like, from a patient's vasculature. It is desirable for the invention to provide an intravascular treatment device for removing soft tissue obstructions from a vascular lumen, such as that located within the peripheral vasculature, for example. Ideally, the invention also provides novel methods for removing vascular occlusions, especially soft tissue occlusions.